Reinforced, dynamic lifting anchor for a structural member

ABSTRACT

A lifting anchor for a structural member, such as a concrete panel, includes a head part able to be coupled with a gripping ring, a foot and a body interposed between the head and the foot, the head and the foot being intended to be embedded in the material of which the structural member is made, the anchor being obtained by folding at least one flat defining different successive portions that form the head, the body and the foot, respectively, of the anchor. The constituent portions of the foot of the anchor include two lower branches that diverge on either side of the body of the anchor. The anchor includes a reinforcing part interposed between the two flats or flat portions, extending from the head of the anchor along at least a part of the body.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Phase Entry of International Patent Application No. PCT/FR2016/050181, filed on Jan. 28, 2016, which claims priority to French Patent Application Serial No. 15/57735, filed on Aug. 14, 2015, both of which are incorporated by reference herein.

BACKGROUND AND SUMMARY

The invention relates to a dynamic anchor for lifting a structural member, such as a horizontally cast concrete panel, in particular, which makes it possible to lift said panel without any mechanical means nor additional framing.

Such anchor knowingly comprises a head part able to be coupled with a gripping ring, a foot and a body interposed between the head and the foot, with the head and the foot being intended to be embedded in the material which the structural member is made of, with the anchor being obtained by folding at least one flat defining different successive portions that form the head, the body and the foot of the anchor, respectively. An anchor comprising a stiffening frame, formed at the anchor foot by two opposite diverging flat branches and two converging lower branches, has the advantage of maintaining the angle of the diverging branches and thus the amplitude of the compression cone generated upon lifting a structural member. Such type of anchor is however not specifically adapted to the lifting of particularly heavy structural members, and the field of application thereof is thus restricted. The invention aims to solve these disadvantages.

For this purpose, the invention relates to a lifting anchor for a structural member, such as a concrete panel, comprising a head part able to be coupled with a gripping ring, a foot and a body interposed between the head and the foot, with the head and the foot being intended to be embedded in the material which the structural member is made of, with the anchor being obtained by folding at least one flat defining different successive portions that form the head, the body and the foot, respectively, of the anchor, with the constituent portions of the foot of the anchor comprising two lower branches that diverge on either side of the body of the anchor, and two branches that converge towards one another and extend from the diverging branches. According to the invention, the anchor comprises a reinforcing part interposed between the two flats or flat portions, extending from the head of the anchor along at least a part of the body.

The invention may also provide for one and/or the other of the following aspects:

-   -   the reinforcing part is in the form of a flat.     -   the reinforcing flat extends half-way up the body of the anchor.     -   the reinforcing flat extends up to the lower ends of the         converging branches.     -   The anchor comprises means for locking the converging branches         against one another.     -   the means for locking one converging branch to the other         comprise at least one protrusion formed on the lower free edge         of the converging branch, and a recess for accommodating such         protrusion, provided in the thickness of the opposite diverging         branch from the lower free edge thereof, with the protrusion         being engaged into the recess when the portions of the flat         heads of the anchor and the reinforcing part interposed between         same, are pressed against each other.     -   the locking means comprise a single protrusion transversally         offset relative to the center of the free edge of the diverging         branch, and a cut forming the accommodating recess, with the two         lower free edges of the two converging branches each comprising         a single protrusion and one cut.     -   the locking means comprise several protrusions and several cuts,         with the protrusions and the cuts alternating along the lower         free edge of the converging branch, with the two lower free         edges of the two converging branches each having several         protrusions and several cuts forming notches.     -   The anchor is formed by two identical flats assembled on either         side of the reinforcement.     -   the reinforcement comprises a hole for the passage of the         locking means provided in the thickness of same.     -   the anchor comprises at least one outer tilt-up rib 31 on each         of the external faces of the two paired flats.     -   the outer rib 31 extends along a longitudinal axis of the anchor         A-A′ or along an inclined direction relative to such axis.     -   the two paired flats 12 a, 12 b, and/or at least one of the         flats 12 a, 12 b and the central reinforcement 20 are secured         together by means of a material bridge formed by a portion of a         flat folded along a folding line 33, 36, 37.     -   the folding line 33, 36, 37 extends along a side edge of the         anchor head, or an upper edge of the anchor head or a lower edge         of the anchor foot.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described while referring to the appended figures which schematically show the various embodiments of the invention, among which:

FIGS. 1 and 2 show perspective views of an anchor according to a first embodiment of the invention, not assembled (FIG. 1) and assembled (FIG. 2);

FIGS. 3 and 4 show perspective views of an anchor according to a second embodiment of the invention, not assembled (FIG. 3) and assembled (FIG. 4);

FIGS. 5 and 6 show perspective views of an anchor according to a third embodiment of the invention, not assembled (FIG. 5) and assembled (FIG. 6);

FIGS. 7A and 7B show an alternative embodiment of a lifting and tilt-up anchor advantageously provided with two longitudinal ribs that protrude outwards from the side faces of the two flats, and respectively in a front view 7A and a perspective view 7B, with FIG. 7A further illustrating, in dotted lines, the possibility of interposing a central reinforcement between the two flats provided with the external longitudinal ribs;

FIGS. 8 to 11 show perspective views of an alternative embodiment of the assembly of two flats constituting a not reinforced anchor (FIGS. 8 to 10), and a reinforced anchor (FIG. 11) enabling a relatively stationary holding of the various flats constituting the anchor; and

FIG. 12 schematically shows a flat view of the various flats constituting the anchor of FIG. 11 and the junctions thereof in pairs.

DETAILED DESCRIPTION

According to the appended figures, the anchor according to the invention comprises a head part 1, a part 2 forming the body of the anchor and a part 3 forming the foot. Except for the head 1 which remains outside the material of the structural member and which is adapted to be hooked to a handling device, the anchor is intended to be embedded in the material which the structural member is made of, for which structural member the anchor aims at facilitating the handling. Generally speaking, such structural member may be a concrete slab or panel, and the head 1 of the anchor is accessible from a free section of the panel within which a recess or “reservation” has been provided for, which lets the anchor head 1 out, whereas the anchor body 2 and foot 3 are embedded in concrete.

According to FIG. 3, the anchor is made from two identical flats 12 a, 12 b, i.e. two rigid strips, for instance made of metal, the thickness of which is low relative to the width thereof, which are each folded along four folding lines C, D, A, B so as to successively define, for the considered flat, and according to FIG. 1 (with the references associated with letter “a” relating to flat 12 a, with the references associated with “b” relating to flat 12 b):

a vertical head part 6 a pressed against the head part 6 b of the other flat, extending in a plane P,

a branch 7 a, 7 b which extends under the head part 6 a and diverges above the plane formed by such head part, along a low angle of approximately 15° for example, with the two branches of the two flats diverging from each other in the direction of the anchor foot,

a converging branch 8 a, 8 b which extends under the branch 7 a on a more or less significant length, for example of approximately 8 to 13 cm, which makes it possible to hold the anchor foot deep inside the structural member,

a lower diverging branch 9 a inclined above the main plane of the flat P defined by the anchor head 6 a, 6 b, at an angle of about 70°,

a converging branch 10 a which extends under the diverging branch to join the plane P and to have the lower end resting against that of the converging branch 10 b of the other flat.

Such flats are generally less than 15 mm thick, in order to enable the folding thereof along the folding lines A-D. Such anchor, having two paired flats is so positioned in the panel that the plane wherein the width of the flats is inscribed is the same as the tilt-up plane. The lower diverging branches 9 a, 9 b define active faces which, when combined with the developed surface of the flat, make it possible to stress both the adherence and shearing of concrete at right angles with the anchorages generated by the surfaces.

Because they are inclined relative to the main plane P, such branches 9 a, 9 b define, upon lifting, a compression area centered on the main plane of the anchor, the apex of which is located towards the anchor foot and the base of which extends about the anchor head. The amplitude of the base of the compression area is greater when a branch 9 a, 9 b is inclined by almost 45°, and smaller when such inclination is close to a horizontal plane. The converging branches 10 a, 10 b which, according to such embodiment, are in mutual contact by their lower end edges, make it possible to keep the inclination of the diverging branches constant relative to the longitudinal plane P of the flat when lifting the panel.

The anchor may also comprise a reinforcing part interposed between the two flats to increase the strength of the anchor and thus enable the lifting of particularly heavy structural members. According to a special embodiment, the reinforcing part consists of a plate 13, preferably having a length and a width substantially similar to those of a protrusion of the flats 12 a, 12 b between which it is positioned in the plane P. The plate, positioned in the plane P, thus has an upper end portion engaged between the end parts of the two flats defining the head of the anchor, with the lower end being held between the lower edges of the lower converging branches 10 a, 10 b.

In order to make it possible to lock the two converging branches 10 a, 10 b relative to the reinforcing plate, such two branches 10 a, 10 b and the portion opposite the plate, comprise mutual locking means. In the example shown in figure FIG. 1, such additional means comprise two flat 21 protrusions which respectively extend the two converging branches 10 b beyond the two lower transversal edges 22 thereof, and an opening 24 is provided in the thickness of the reinforcing plate 20 so as to accommodate the two protrusions 21 of the two converging branches 10 a, 10 b. Such opening will be so formed as to accommodate the two protrusions, i.e. it will have a width slightly greater than the added width of the two protrusions, and a height which will take account of the inclination of such protrusions (which is that of the converging branches) so as to make it possible to insert same into the opening when simply moving both flats 12 a, 12 b towards the plate 20.

In the examples of FIGS. 1 to 4, the protrusions of the two converging branches are mutually offset relative to the longitudinal axis Al-Al′ of each flat so as to enable the simultaneous insertion thereof into the opening. As a matter of fact, the protrusions of the two flats are shifted relative to the axis Al-Al′ by the same distance, so that both flats are identical and can be positioned on either side of the plane P. In fact, the protrusions are each so positioned as to be able to be adjacent upon assembling the flats around the plate 20, i.e. with a side edge coinciding with the axis Al-Al′.

The anchor according to the FIGS. 1 and 2 also comprises two flats 12 a, 12 b assembled on either side of a reinforcing plate 20, the converging branches 10 a, 10 b of which are provided with protrusions 21 which engage into a matching opening 24 of the plate 20, and the protrusions and the opening comply with the description above, which refers to the FIGS. 3 and 4, but the bodies 2 of the two flats have no diverging and converging intermediate faces, so that the body 2 of each flat simply extends from the head 6 a, 6 b in the plane P. In the example shown in FIGS. 5 and 6, the reinforcing plate 20 interposed between the two flats 12 a, 12 b does not extend on the length of the protrusion in the plane P of the two flats, but substantially half-way of the flat body. Therefore, it does not need being provided with an opening for the passage of the protrusions of the converging branches since it remains interposed between the head portions and the upper part of the anchor body.

The converging branches are provided with means for directly locking same together, which are matching notches 26 provided on the lower transversal edges of the branches. The two facing flats with notches ideally are identical. The recessed parts of the notches of a converging branch enable the protrusions of the notches of the other converging branch to engage. In both discussed embodiments, the reinforcement can be attached to the two flats, by means of rivets, at the anchor head and/or the anchor body. The central reinforcement can be provided between two ribbed flats constituting the anchor.

More precisely, and according to the alternative embodiment illustrated in FIGS. 7A and 7B, the anchor may comprise two longitudinal ribs 31 which protrude outwards the outer side faces 32 of the two flats. Such longitudinal ribs make it possible to obtain an efficient lifting and tilting anchor since the flat mass of concrete is trapped above the upper surface of the ribs when the panel is tilted from a horizontal position to a vertical position. Such outer ribs can be formed by recessing the flats of one anchor using a punch with a shape adapted to the desired rib shape. According to such shape, the optimum tilting stress profile can be obtained. The shape of each rib can thus be optimized to reach this objective.

In the illustrated example, the anchor consists of two paired flats which form together a foot with diverging branches 9 a, 9 b specifically at 45° and underlying converging branches 10 a, 10 b forming an angle of approximately 60°-70° with the converging branches, intermediate adherence faces 7 a, 7 b, 8 a, 8 b the upper faces 7 a, 7 b of which form an angle (3 of approximately 15° with the plane P, and the lower faces 8 a, 8 b form an angle y of approximately 160° with the matching upper face. In this example, the outer rib 31 extends along a lower portion of the upper face 7 a, 7 b, extends on the lower face 8 a, 8 b up to the vicinity of the foot (difference of approximately 1/10 of the total length of the anchor). It has a width equivalent to approximately one fourth of the width of the flat, and the height of the outer bump it forms is equivalent to the thickness of the flat.

In the illustrated example, the rib has a generally oblong shape. It may advantageously have a substantially triangular shape. Of course other rib profiles can be considered, as well as other implantations on the flat. Several external ribs can specifically be provided on the outer faces of the flats, may extend on a more or less significant length, be more or less inclined relative to the mid line of the anchor, not straight, broken, interrupted . . .

An anchor with paired flats may also include flats provided with external ribs and may not necessarily be provided with a central flat. Besides, as shown in FIGS. 11 and 12, the central reinforcement 20 can be secured to one of the two flats 12 a using a folding line of the flat 33 interposed as shown in FIG. 12, between two flat portions in an end-to-end engagement in the “flat” or “not shaped yet” configuration of the anchor and forming, when the anchor is shaped, the central reinforcement 20 and one of the two flats 12 a. According to FIG. 11, such folding line 33 coincides with the lower end of the anchor foot when shaped.

Besides, the reinforcement 20 can be secured to the other flat 12 b using a second folding line 36 interposed as shown in FIG. 12, between two flat portions side by side in the “flat” configuration of the anchor, and forming the central reinforcement 20 and the other flat 12 b when the anchor is shaped. The second folding line 36 coincides with an upper side portion of the anchor.

As shown in FIGS. 8 to 9, when the anchor has no central reinforcement, assembling two flats together by folding or flat fold integral with two flats and forming a junction between same, can be achieved at the lower end of the anchor, between the two converging branches of two flats constituting the anchor (FIG. 8) thanks to the folding line 33, on a side portion of the anchor head (FIG. 9) between the two side edges of the two head portions of two flats paired by the folding line 36, or at the upper end of the anchor, between the two upper edges of the two head portions of the two paired flats (FIG. 10) by the folding line 37. The “pattern” from which such three anchors are formed comprises:

-   -   FIG. 8: two flat portions in end-to-end alignment, the length of         which coincides with the deployed length of each shaped flat,         with these two flat portions being separated by a line,         half-way, which is liable to be the folding line 33. The flat         will comprise additional folding lines so as to define two         slightly diverging upper branches (for example at 15° relative         to the plane P), two upper converging branches joining the plane         P, and one stiffening frame with 45° diverging branches and         converging branches at an angle of approximately 80°. The total         length of the anchor can ideally range from 100 to 400 mm, the         width of the flat can be 20, 25, 30, 40, 60 or 80 mm, the         thickness of the flat can range from 3 to 8 mm.     -   FIG. 9: two flat portions positioned side by side and joined by         a flat bridge, the width of which is almost equal to two flat         thicknesses, with the mid line of such material bridge being         liable to be the folding line 36,     -   FIG. 10: two flat portions in end-to-end alignment, having a         length which coincides with the deployed length of each shaped         flat, with these two flat portions being separated by a line,         half-way, which is liable to be the folding line 37, and         positioned at a shrunk part intended to form the upper edge of         the anchor with a smaller width than the rest of the anchor head         and body.

As it appears from the description above and the figures, the anchor according to the invention has major advantages relative to the anchors of the state of the art. An anchor of this type is produced using a simple and inexpensive manufacturing method based on the folding of a single or of two flat(s) which makes it possible to lift relatively heavy structural members, thanks to the reinforcement. Of course, the special features of the embodiments, such as the square-, triangle- or diamond-sectioned shape of the box, the 10, 20, . . . 45 degree inclination of the lower diverging branches, the presence or the absence of upper diverging branches within the anchor body, the number thereof, may be combined together in order to define an optimum anchoring according to the structural member to be lifted. One or more reinforcement(s) may also be provided between the flats of the anchor, with such reinforcements further possibly having various shapes, in addition to flats. 

1. A lifting anchor for a structural member, comprising a head part able to be coupled with a gripping ring, a foot and a body interposed between the head and the foot, with the head and the foot being intended to be embedded in the material of which the structural member is made, with the anchor being obtained by folding at least one flat defining different successive portions that form the head, the body and the foot, respectively, of the anchor, with the constituent portions of the foot of the anchor comprising two lower branches that diverge on either side of the body of the anchor, and two branches that converge towards one another and extend from the diverging branches, and a reinforcing part interposed between the two flats or flat portions, extending from the head of the anchor along at least a part of the body.
 2. An anchor according to claim 1, wherein the reinforcing part is in the form of a flat.
 3. An anchor according to claim 2, wherein the reinforcing flat extends half-way up the body of the anchor.
 4. An anchor according to claim 1, wherein the reinforcing flat extends up to the lower ends of the converging branches.
 5. An anchor according to claim 1, further comprising a lock operably locking the converging branches against one another.
 6. An anchor according to claim 5, wherein the lock operably locks one converging branch to the other comprise at least one protrusion formed on the lower free edge of the converging branch, and a recess for accommodating such protrusion, provided in the thickness of the opposite converging branch from the lower free edge thereof, with the protrusion being engaged into the recess when the portions of the flat heads of the anchor and the reinforcing part interposed between same, are pressed against each other.
 7. An anchor according to claim 6, wherein the lock comprises a single protrusion transversally offset relative to the center of the free edge of the converging branch, and a cut forming the accommodating recess, with the two lower free edges of the two converging branches each comprising a single protrusion and one cut.
 8. An anchor according to claim 6, wherein the lock comprises several protrusions and several cuts, with the protrusions and the cuts alternating along the lower free edge of the converging branch, with the two lower free edges of the two converging branches each having several protrusions and several cuts forming notches.
 9. An anchor according to claim 5, wherein the reinforcement comprises a hole for the passage of the lock provided in the thickness of same.
 10. An anchor according to claim 1, wherein the anchor is formed by two identical flats assembled on either side of the reinforcement.
 11. An anchor according to claim 1, further comprising at least one outer tilt-up rib on each of the external faces of the two paired flats.
 12. An anchor according to claim 11, wherein the outer rib extends along a longitudinal axis of the anchor or along an inclined direction relative to such axis.
 13. An anchor according to claim 1, wherein the two paired flats, and/or at least one of the flats and the central reinforcement are secured together by means of a material bridge formed by a portion of a flat folded along a folding line.
 14. An anchor according to claim 13, wherein the folding line extends along a side edge of the anchor head, or an upper edge of the anchor head or a lower edge of the anchor foot. 